EWS Managed Api - 仅检索一次日历项目

Question

我有一个 windows 服务可以从 Exchange 中读取日历项目并将它们存储在我的应用程序的数据库中，供每个用户使用。现在我想知道将 Exchange 上的项目标记为在存储后不在下一个服务运行中检索的最佳方法是什么？

我尝试将扩展的属性添加到日历项并设置它的值，然后每次都根据它的值进行搜索：

DateTime startDate = DateTime.Now;
DateTime endDate = startDate.AddDays(60);
const int NUM_APPTS = 60;    
// Set the start and end time and number of appointments to retrieve.
CalendarView cView = new CalendarView(startDate, endDate, NUM_APPTS);

Guid myPropertyId = new Guid("{XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX}");
ExtendedPropertyDefinition myExtendedProperty = new ExtendedPropertyDefinition(myPropertyId, "SyncFlag", MapiPropertyType.Boolean);

// Limit the properties returned to the appointment's subject, start time, end time and the extended property.
 cView.PropertySet = new PropertySet(AppointmentSchema.Subject, AppointmentSchema.Start, AppointmentSchema.End, AppointmentSchema.Location, myExtendedProperty);

// Retrieve a collection of appointments by using the calendar view.
List<SearchFilter> searchFilterCollection = new List<SearchFilter>();
searchFilterCollection.Add(new SearchFilter.IsEqualTo(AppointmentSchema.Start, DateTime.Now));
searchFilterCollection.Add(new SearchFilter.IsEqualTo(AppointmentSchema.End, DateTime.Now.AddDays(60)));

searchFilterCollection.Add(new SearchFilter.IsNotEqualTo(myExtendedProperty, true)); //Do not fetch already marked calendar items

SearchFilter searchFilter = new SearchFilter.SearchFilterCollection(LogicalOperator.And, searchFilterCollection);

FindItemsResults<Item> appointments = service.FindItems(WellKnownFolderName.Calendar, searchFilter, cView);

使用此代码搜索日历项会引发此异常：

Restrictions and sort order may not be specified for a CalendarView.

我也不确定这是否是最好的方法。有什么想法吗？

谢谢

Answer 1

一种方法是使用 SyncFolderItems 方法。它将 return 自上次调用以来更改的项目。您所要做的就是在每次调用之间保存同步 "cookie"。

您还应过滤掉自上次通话后创建的约会项目。

下面的代码片段应该可以解决问题。

static private void GetChangedItems()
{
    // Path to cookie
    string syncStateFileName = @"c:\temp\ewssyncstate.txt";

    try
    {
        var service = GetServiceAP();
        bool moreChangesAvailable = false;

        do
        {
            string syncState = null;


            if (File.Exists(syncStateFileName))
            {
                // Read cookie
                syncState = File.ReadAllText(syncStateFileName);
            }

            ChangeCollection<ItemChange> icc = service.SyncFolderItems(new FolderId(WellKnownFolderName.Calendar), PropertySet.FirstClassProperties, null, 10, SyncFolderItemsScope.NormalItems, syncState);

            if (icc.Count == 0)
            {
                Console.WriteLine("There are no item changes to synchronize.");
            }
            else
            {
                syncState = icc.SyncState;

                // Save cookie
                File.WriteAllText(syncStateFileName, syncState);

                moreChangesAvailable = icc.MoreChangesAvailable;

                // Only get appointments that were created since last call
                var createdItems = icc
                    .Where(i => i.ChangeType == ChangeType.Create)
                    .Select(i => i.Item as Appointment)
                    ;

                if (createdItems.Any())
                {
                    service.LoadPropertiesForItems(createdItems, PropertySet.FirstClassProperties);

                    foreach (Appointment appointment in createdItems)
                    {
                        Console.WriteLine(appointment.Subject);
                    }
                }
            }
        }
        while (moreChangesAvailable);

    }
    catch (Exception ex)
    {
        Console.WriteLine(ex.ToString());
    }
}

EWS Managed Api - 仅检索一次日历项目

EWS Managed Api - Retrieve calendar items only once

c#

exchange-server

exchangewebservices

outlook-calendar

ews-managed-api